Sewing-machine drive pulley



June 22 1926. 1,589,966

F. F. HILLIX SEWING MACHINE DRIVE PULLEY Filed August 29 192 5/ FIG 4 Invenfor 7714; 7

Afforneys Patented June 22, 1926.

PATENT QFFMIE.

FOSTER F. I-IILLIX, OF CLEVELAND, GHIO, ASSIG NOR, BY MESNE ASSIGNMENTS, T \VI-IITI} SEWING MACHINE CORPORATION, OF CLEVELAND, OHIO, A. CORPORATION OF DELAWARE.

SEVIING-MACHINE DRIVE PULLEY.

Application filed August 29, 1924. Serial No. 734,880.

This invention relates to a friction wheel adapted to have a resilient contact with the driven member. An illustration of a particularly advantageous use is the mounting of it upon the armature shaft of a small motor acting to drive the fly wheel of a sewing machine.

An object of the invention is to provide a simple friction wheel, capable of being cheaply manufactured, and which shall be very durable in use, retaining its shape, uniformity and resiliency for a long period. In making such wheels it has been custonr ary to mount a rubber disc or body upon a suitable ferrule or bushing bet-ween radial flanges. The difliculties have been that the resilient material did not maintain a true uniform surface, particularly when rotated at very high speeds, nor did it long retain an even contact with the surface of the driven member. I have found that if the body of such a wheel or resilient material, such as rubber, is put under considerable compression and the radial and transverse stresses equalized near the driving face, and made very great comparatively, that the surface of such a wheel can be maintained under a constant stress throughout its life. The result will be permanently true uniformity of contact surfaces, and excellent frictional or gripping effect and great wearing life.

The above and other advantages will become apparent from the following description relating to the drawings which illustrate a preferred embodiment of this present invention. The essential characteristics of my invention are summarized in the claims.

In the drawings Fig. 1 is a diagrammatic side elevation of a sewing machine head illustrating a motor carrying on its armature shaft such a wheel in contact with the hand wheel of the sewing machine; Fig. 2 is a front sectional view of the parts of the wheel before assembling; Fig. 3 is a similar view with the parts brought together; Fig. 4: is an outside elevation of my completed wheel; Fig. 5 is a diagrammatic view illustrating the effect of the radial and transverse forces resulting from compression.

Referring to the drawings by the use of numerals, 1 indicates a sewing machine; 2

a suitable motor mounted upon the side thereof; 8 is the usual hand wheel mounted upon the armature shaft of the motor and in contact with the surface of the hand wheel 3. My friction wheel as shown has a suitable ferrule or sleeve 10 adapted to embrace an armature shaft and having an enlarged head 12 with a radial opening threaded as at 13 to receive a suitable clamping screw 14:, adapted to secure the pulley at its desired position on the armature shaft. 15 indicates a thick disk of suitable resilient material, such as rubber or the like. Its periphery may have any suitably shaped suriace, here indicated in Fig. 2 as concave. The flanges and 21 are shown as suitable saucer or dlslr-shaped washers adapted to fit closely upon the ferrule 10 and embrace the resilient material. As the washers are brought together upon the sides of the rubber, as indicated at Fig. 3, they are pressed very forcibly against the same, causing the rubber to bulge outwardly as indicated, into a substantially conical pos tion which preferably is normally slightly concave, the rubber naturally pressing outwardly over the periphery of the inturned edges of the flanges 20 and 21, as shown. Subsequent slight'trimming of the material brings it to a more regular and true surfaces indicated at Fig. l.

In Fig. 5 I have shown radial arrows 25 indicating the pressure of the resilient m1:- terial tending to cause it to flow outwardly due to the transverse compression forces be" tween the inturned edges of the tlange mi /lit hers 20 and 21, which forces indie 'ted by the arrows 25. The pressure away from the center is resisted by the tensional strength of the material located outside of the flanges which is subjected to increased tensional stress as the pressure between the flanges increased. A condition is reached where the forces are balanced leaving the circumference of the pulley under a very much stressed condition. It. is imperative that the circumferential stress set up in the surface is great enough that at no time will the centrifugal force set up by the rotation of the pulley at high speeds distort the pulley from its original accurate shape. At the same time inwardly acting forces are set up by the wedging action of the concave side members, establishing the balance of this outward pressure, after the rubber has assumed substantially the position indicated in Fig. 3. This, by the Way presents a suburi'ac The body s or" the esrure b which on it. This in- D a lorce, as indicated by the arrows L? \vnci establishes a substantial balance of the static condition ot the compres rubber directly l'etiveen the periphoral i1 icr edges 0 f these it It will be lit-"tr that the Eia coextel'isire with resoe' body so that tiallv the of balancet ion of the resulti V '7 ,i

ient nmternrl or V I the periphei body is originally curved inwardly is sh .vn at 16, it may subswintially true :i ustro-cobrought to t l L ioidal sill-"face. Should another surface, such a true reg 'ular surface be desired, it is a very irnoie latter to cut or body atte a ning it rap leave the su s pression at all time; of its use. Thus, the surface and the high ei'iect of such a stre. much greater Wear are accomplished.

The conditions descrioed l in a Wheel suitable for oriviin' machine and being approxin in diameter. For ena nple, by discs together upon the rubber ma 1. and securing; them While subjected to a pres sure oi? say three hundred to th- .e hu idred be up a sewing nd titty pounds. The mate. lal used is known as a. stock c niposition similar to that of tire treads and the like but, of cour 0, both the materials and the pressures may be varied according to the conditions desired and the size of the Wheel to be made. l i hen the discs are secured, as described, a more ie running Wheel nu y be obtained I that is, by removing a few idthsot an inch ot the body of the ii t stool:- While rotating the Wheel at a. high speed on true running arbor. This insu s that the wheel will be accurate and the grinding may be done at substantially the same speed at which the Wheel will. be later used.

Another advantage of this invention is the bringing together of the side members vith their inwardly facing concave surface so that a p rt-ion of the material being urged inwardly causes a very clos tight fitting engagement of the material with the hub member 10, and this with the very tight grip of the edges of the concave flanges as described is entirely adequate to prevent relative rotation of the body and hub, and the necessity for an angular hub or for a key or like securing means is eliminated.

Having thus described my invention, I claim:

1. A friction drive Wheel having a hub, abody of resilient material fitted over the hub, and concave side securing flange members forcibly pressed against the material and secured in that POSLLlGIl so that the re silient material is under great compression directly between periphehies of the flange members, while the outvzrd and inwzrd radial forces are balanced substantially at the periphery of t 1e liaody and the resilient material is all times under stress.

2. A friction \vnecl consisting of a hub, a :o-c y of resilient material titted over the .nd inwardly 'urned flange men'ibers at .:'de oi the hub forced against the body .to distort it invardly and outvrardcasing}; 'reat compression between the :cs of the flange members, and causing a gi rip iing of the material between and hub, whereby the body has onuition of stress. l friction Wheel consisting of the hub, resilient n aterial fitted over the 5 d inwardly turned flange n inbers net the sides of the body material inwardly and outwardly, causnn'e'ssion between the edges of i l 1 A the bangle members and the body material but a slight distance beyond the edges of the flanges, wher by a static con tion of stress is naintained substantially at e of the bot-.y.

Lion drive wheel consisting of a "'ent raterial embracing the hub, so-like members concave on their nounted on the hub and 1- therefrom substantially 'i ihery of the body and forcibly the body to cause the mateto eiqrnd outwardly and be pressed inst the hub, and means for ree ilan es in position to raii tain 1 ion, the periphery of ie body t even drivingsurface under friction drive wheel consisting; of u hub, a body of resilient material embracing the hub, inwardly concave flange members mounted on the hub and extending outwardly thereir in forcibly pressed against the LOlllpl' A body to cause the n terial to expand outwardly and to be forced inwardly against the hub, means for securing the flanges in the position compressing the body material, the periphery of the body presenting a regular surface a all times under compression, the side ilange members and the body being substantially co X'ensive at the respective sides.

In testimony whereof, I hereunto affix my ignature.

seems r. HILLIX. 

